Genetic genealogy is the use of DNA testing in combination with traditional genealogical and historical records.[1] Genetic genealogy involves the use of genealogical DNA testing together with documentary evidence to infer the relationship between individuals.

Genealogical DNA testing first became available on a commercial basis in the year 2000 with the launch of Family Tree DNA and Oxford Ancestors. Since then other companies have been established, dozens of relevant academic papers have been published, and thousands of private test results organised by surname study groups have been made available on the internet. The comparison of results may be complicated by the fact that some laboratories use different markers and report the results in different ways. By 2007 annual sales of genetic genealogy tests for all companies, including the laboratories that support them, were estimated to be in the region of US $60 million.[2] By January 2013 it was estimated that around two and a half million people around the world had paid for a consumer genomics test, with the majority of participants testing for genealogical purposes.[3]

History

The earliest use of the term genetic genealogy found to date was on 20 February 1989 in an article by Tom Siegfried in the Dallas Morning News entitled "Genetic genealogy and the search for 'Eve":

"In searching for the roots of the human race, scientists have traditionally relied on the fossil records found in ancient rocks. Of course, scientists have long known that we all carry a record of our roots in our genes. It's just that the record in the rocks has been easier to read. Lately, though, practitioners of genetic genealogy have found methods to search for the woman from whom we all are descended. She is popularly known as Eve."[4]

The next recorded reference was in June 1996 when Helene Cincebeaux gave a presentation on the subject of "Genetic Genealogy" at the Federation of East European Family History Societies' conference in June 1996 in Minneapolis.[5]

The first published reference to the use of the term in the context of a surname DNA project was on 9 November 1998 with the publication of an online article entitled "An introduction to genetic genealogy" by the genealogist Alan Savin, who launched the first surname project by a genealogy hobbyist in 1997.[6][7][8][9]

Y-chromosome DNA tests

Y-DNA testing involves short tandem repeat (STR) and, sometimes, single-nucleotide polymorphism (SNP) testing of the Y-chromosome. The Y-chromosome is present only in males and reveals information on the patrilineal line. These tests can provide insight into the recent (via STRs) and ancient (via SNPs) genetic ancestry. A Y-chromosome STR test will reveal a haplotype, which should be similar among all male descendants of a male ancestor. SNP tests are used to assign people to a patrilineal haplogroup, which defines a much larger genetic population. A Y-DNA test is typically used in surname research and results are collated within surname DNA projects.

Mitochondrial DNA testing

mtDNA testing involves sequencing or testing the HVR-1 region, HVR-2 region or both. An mtDNA test may also include the additional SNPs needed to assign people to a matrilineal haplogroup. Family Tree DNA offers a full mitochondrial sequence (FMS) test which sequences the entire mitochondrial genome.

Autosomal DNA testing

Biogeographical and ethnic origins

Additional DNA tests exist for determining biogeographical and ethnic origin, but these tests have less relevance for traditional genealogy.

Videos

The three main types of DNA test (Y-DNA, mtDNA and autosomal DNA) are explained in this video presentation entitled DNA - Brick Wall Buster? by Maurice Gleeson which was the subject of the Irish Genealogical Research Society's Spring Lecture presented at the National Library of Ireland in Dublin on 19th March 2013.

Drawbacks

People who resist testing may cite one of the following concerns:

Cost

Quality of testing

Concerns over privacy issues

Loss of ethnic identity

Finally, Y-DNA and mtDNA tests each only trace a single lineage (one's father's father's father's etc. lineage or one's mother's mother's mother's etc. lineage). At ten generations back, an individual has up to 1024 unique ancestors (fewer if ancestor cousins interbred) and a Y-DNA or mtDNA test is only studying one of those ancestors, as well as their descendants and siblings (same sexed siblings for Y-DNA or all siblings for mtDNA). However, most genealogists maintain contact with many cousins (1st, 2nd, 3rd, etc., with different surnames) whose Y-DNA and mtDNA are different, and thus can be encouraged to be tested to find additional ancestral DNA lineages.